Mechanism for signaling buffer status information

ABSTRACT

There is provided a mechanism for reporting buffer status information to a communication network control element when transmission via both a licensed and an unlicensed spectrum is conducted and offloading of traffic is executed. After an offloading value indicating the amount of traffic which can be offloaded from a transmission over a licensed spectrum to a transmission over an unlicensed spectrum is estimated, the UE determines a buffer size of at least one transmission buffer used in a transmission over the licensed spectrum and the unlicensed spectrum. Then, buffer status information is sent to the eNB wherein the estimated offloading value is considered. The eNB can then allocate resources for the transmission over the licensed band while benefits by the offloading to the unlicensed band are considered in the resource allocation.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a mechanism usable for signaling bufferstatus information for communication over licensed and unlicensedspectrum. In particular, the present invention is related toapparatuses, methods and computer program products providing a mechanismby means of which buffer status information can be signaled to thenetwork wherein communication resources in licensed and unlicensedspectrums are considered, in particular in an offloading case wheretraffic is offloaded from a transmission via one spectrum to atransmission via another spectrum.

2. Related Background Art

Prior art which is related to this technical field can e.g. be found bythe technical specification 3GPP TS 36.321, for example according toversion 10.2.0.

The following meanings for the abbreviations used in this specificationapply:

-   ABS: actual buffer size-   BS: base station-   BSR: buffer status report-   D2D: device-to-device-   DL: downlink-   eNB: enhanced node B-   EGTA: estimated offloading traffic amount-   ISM: industrial, scientific and medical-   LTE: Long Term Evolution-   LTE-A: LTE Advanced-   LS: licensed spectrum-   MAC: medium access control-   NM: normal mode-   OM: offloading mode-   RB: radio bearer-   RBG: radio bearer group-   RRC: radio resource control-   VBS: virtual bearer size-   UE: user equipment-   UL: uplink-   UL-SCH: uplink shared channel-   US: unlicensed spectrum

In the last years, an increasing extension of communication networks,e.g. of wire based communication networks, such as the IntegratedServices Digital Network (ISDN), DSL, or wireless communicationnetworks, such as the cdma2000 (code division multiple access) system,cellular 3rd generation (3G) communication networks like the UniversalMobile Telecommunications System (UMTS), enhanced communication networksbased e.g. on LTE, cellular 2nd generation (2G) communication networkslike the Global System for Mobile communications (GSM), the GeneralPacket Radio System (GPRS), the Enhanced Data Rates for GlobalEvolutions (EDGE), or other wireless communication system, such as theWireless Local Area Network (WLAN), Bluetooth or WorldwideInteroperability for Microwave Access (WiMAX), took place all over theworld. Various organizations, such as the 3rd Generation PartnershipProject (3GPP), Telecoms & Internet converged Services & Protocols forAdvanced Networks (TISPAN), the International Telecommunication Union(ITU), 3rd Generation Partnership Project 2 (3GPP2), InternetEngineering Task Force (IETF), the IEEE (Institute of Electrical andElectronics Engineers), the WiMAX Forum and the like are working onstandards for telecommunication network and access environments.

Recently, so-called “proximity-based” applications and services cameinto the focus of further developments in the field oftelecommunications. The term proximity-based applications and servicesmay be used, for example, in cases where two or more devices (i.e. twoor more users), which are close to each other, are interested inexchanging data, if possible, directly with each other.

Currently, such “proximity-based” applications operate fully “over thetop” and are based on “high-level software”, typically relying on a mixof GPS location and of the 3GPP mobile systems used as “data pipes”.

However, such an approach presents fundamental technology limitationsfrom the point of view of e.g. device battery life (due to the extensiveGPS usage), signaling load to the network (due to the required uplinkbursty traffic) and simplicity (due to the “proactive” behavior requiredof the user, e.g. the “check in”).

While the use of an unlicensed-spectrum communication can address someof the aspects mentioned earlier, it still presents some limitations.For example, discovery processes are being defined based on directmessage exchanges and thus not optimal for operation over longer ranges(hundreds of meters or more), or preserve a reasonable battery life. Forthe same reason, an unlicensed option cannot be expected to scale amonga large number of devices.

For future cellular communication networks, a possible method for suchproximity-based applications and services is the so-calleddevice-to-device (D2D) communication. D2D offers a high communicationspeed, large capacity and a high quality of service which are importantfeatures to be achieved. Advantages achievable by the implementation ofD2D communications in the cellular communication environment are, forexample, an offloading of the cellular system, reduced batteryconsumption due to lower transmission power, an increased data rate, animprovement in local area coverage robustness to infrastructure failuresand also an enablement of new services. This is possible while alsoproviding access to licensed spectrum with a controlled interferenceenvironment to avoid the uncertainties of license exempt band. Due tothis, D2D communication gains more and more attraction and interest.

However, in order to make a D2D communication applicable tocommunication networks, such as those based on 3GPP LTE systems, it isnecessary to evolve a suitable platform in order to intercept the demandof proximity-based applications so that it is possible that devices,such as UEs or the like, can discover each other directly over the air,and potentially communicate directly, wherein a certain level of controlfor the network operator side has to be maintained so that D2Dcommunication makes sense from a system management point of view.

For example, if a device (such as a UE) uses simultaneously licensed(i.e. cellular) and unlicensed spectrum, e.g. via inter-band carrieraggregation methods it is required to enable the network, i.e. acommunication network control element (such as an eNB) which schedulestransmission over the licensed spectrum and allocates also the necessaryresources, to conduct a suitable control balancing the actual need ofresources of the device in question and the totally available resourcesin particular at the licensed spectrum.

SUMMARY OF THE INVENTION

It is an object of the invention to provide an apparatus, method andcomputer program product by means of which an improved mechanism usablefor signaling buffer status information for communication over licensedand unlicensed spectrum. In particular, it is an object of the inventionto provide an apparatus, method and computer program product by means ofwhich a communication network control element can be provided withinformation about an actual requirement of resources on a communicationspectrum, in particular a licensed spectrum, when traffic can beoffloaded to another transmission type or communication spectrum, e.g.an unlicensed spectrum.

This object is achieved by the measures defined in the attached claims.

According to an example of an embodiment of the proposed solution, thereis provided, for example, an apparatus comprising an estimatingprocessing portion configured to estimate an offloading value indicatingan amount of traffic which can be offloaded from a transmission over alicensed spectrum to a transmission over an unlicensed spectrum, adetermining processing portion configured to determine a buffer size ofat least one transmission buffer used in a transmission over thelicensed spectrum and the unlicensed spectrum, and a buffer statusinformation transmission processing portion configured to send a bufferstatus information indicating the buffer size for transmission over thelicensed spectrum under consideration of the estimated offloading value.

Furthermore, according to an example of an embodiment of the proposedsolution, there is provided, for example, a method comprising estimatingan offloading value indicating an amount of traffic which can beoffloaded from a transmission over a licensed spectrum to a transmissionover an unlicensed spectrum, determining a buffer size of at least onetransmission buffer used in a transmission over the licensed spectrumand the unlicensed spectrum, and sending a buffer status informationindicating the buffer size for transmission over the licensed spectrumunder consideration of the estimated offloading value.

According to a further example of an embodiment of the proposedsolution, there is provided, for example, an apparatus comprising abuffer status information receiving portion configured to receive andprocess a buffer status information indicating a buffer size fortransmission over a licensed spectrum, wherein the buffer statusinformation considers an estimated offloading value indicating an amountof traffic which can be offloaded from a transmission over a licensedspectrum to a transmission over an unlicensed spectrum, a resourcedetermination portion configured to determine, on the basis of thereceived buffer status information, required resources for atransmission over the licensed spectrum, and a resource allocationportion configured to allocate the determined. resources to atransmission over the licensed spectrum.

Furthermore, according to the further example of an embodiment of theproposed solution, there is provided, for example, a method comprisingreceiving and processing a buffer status information indicating a buffersize for transmission over a licensed spectrum, wherein the bufferstatus information considers an estimated offloading value indicating anamount of traffic which can be offloaded from a transmission over alicensed spectrum to a transmission over an unlicensed spectrum,determining, on the basis of the received buffer status information,required resources for a transmission over the licensed spectrum, andallocating the determined resources to a transmission over the licensedspectrum.

In addition, according to examples of the proposed solution, there isprovided, for example, a computer program product for a computer,comprising software code portions for performing the steps of the abovedefined methods, when said product is run on the computer. The computerprogram product may comprise a computer-readable medium on which saidsoftware code portions are stored. Furthermore, the computer programproduct may be directly loadable into the internal memory of thecomputer and/or transmittable via a network by means of at least one ofupload, download and push procedures.

By virtue of the proposed solutions, it is possible to signal bufferstatus information for communication over licensed and unlicensedspectrum in such a manner that the network, i.e. a correspondingcommunication network control element, obtains information about howmany resources the device needs. That is, it is possible that thedevice, e.g. a UE, can indicate to the network that it needs actually areduced amount of resources for transmission on one spectrum, e.g. alicensed, due to offloading traffic from this spectrum. Furthermore,according to examples of embodiments of the invention, the proposedmechanism is easy to be implemented as existing signaling procedures canbe used. Furthermore, it is possible to utilize a reinterpretation ofcurrent specified messages but the scheme works also withoutreinterpretation

The above and still further objects, features and advantages of theinvention will become more apparent upon referring to the descriptionand the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a diagram illustrating a configuration of a communicationsystem in which examples of embodiments of the invention can beimplemented.

FIG. 2 shows a diagram illustrating a grouping of radio bearers intoradio bearer groups used as a basis for signaling buffer statusinformation to the network.

FIG. 3 shows a diagram illustrating a structure of buffer status reportsforming an example of buffer status information used in examples ofembodiments of the invention.

FIG. 4 shows a flow chart illustrating a procedure for signaling bufferstatus information conducted in a communication network elementaccording to examples of embodiments of the invention.

FIG. 5 show a flow chart illustrating a procedure for processing bufferstatus information conducted in a communication network control elementaccording to examples of embodiments of the invention.

FIG. 6 shows a block circuit diagram of a communication network controlelement including processing portions conducting functions according toexamples of embodiments of the invention.

FIG. 7 shows a block circuit diagram of a communication network elementincluding processing portions conducting functions according to examplesof embodiments of the invention.

DESCRIPTION OF PREFERRED EMBODIMENTS

In the following, examples and embodiments of the present invention aredescribed with reference to the drawings. For illustrating the presentinvention, the examples and embodiments will be described in connectionwith a cellular communication network based on a 3GPP LTE system.However, it is to be noted that the present invention is not limited toan application using such types of communication system, but is alsoapplicable in other types of communication systems and the like.

A basic system architecture of a communication system where examples ofembodiments of the invention are applicable may comprise a commonlyknown architecture of one or more communication networks comprising awired or wireless access network subsystem and a core network. Such anarchitecture may comprise one or more access network control elements,radio access network elements, access service network gateways or basetransceiver stations, such as a base station (BS) or eNB, with which acommunication network element or device such as a UE or another devicehaving a similar function, such as a modem chipset, a chip, a moduleetc., which can also be part of a UE or attached as a separate elementto a UE, or the like, is capable to communicate via one or more channelsfor transmitting several types of data. Furthermore, core networkelements such as gateway network elements, policy and charging controlnetwork elements, mobility management entities and the like may becomprised.

The general functions and interconnections of the described elements,which also depend on the actual network type, are known to those skilledin the art and described in corresponding specifications, so that adetailed description thereof is omitted herein. However, it is to benoted that several additional network elements and signaling links maybe employed for a communication connection to or from UEs or eNBs,besides those described in detail herein below.

Furthermore, the described network elements, such as communicationnetwork elements like UEs or communication network control elements likeBSs or eNBs, and the like, as well as corresponding functions asdescribed herein may be implemented by software, e.g. by a computerprogram product for a computer, and/or by hardware. In any case, forexecuting their respective functions, correspondingly used devices,nodes or network elements may comprise several means and components (notshown) which are required for control, processing andcommunication/signaling functionality. Such means may comprise, forexample, one or more processor units including one or more processingportions for executing instructions, programs and for processing data,memory means for storing instructions, programs and data, for serving asa work area of the processor or processing portion and the like (e.g.ROM, RAM, EEPROM, and the like), input means for inputting data andinstructions by software (e.g. floppy diskette, CD-ROM, EEPROM, and thelike), user interface means for providing monitor and manipulationpossibilities to a user (e.g. a screen, a keyboard and the like),interface means for establishing links and/or connections under thecontrol of the processor unit or portion (e.g. wired and wirelessinterface means, an antenna, etc.) and the like. It is to be noted thatin the present specification processing portions should not be onlyconsidered to represent physical portions of one or more processors, butmay also be considered as a logical division of the referred processingtasks performed by one or more processors.

In network controlled D2D and in simultaneous use of licensed andunlicensed spectrum by the communication system, such as the LTE system,one commonality is the some level autonomous resource usage by thedevices or UEs in a D2D communication and devices or UEs which arescheduled or use resources on unlicensed spectrum due to regulations(e.g. regulations of ISM), in comparison to usage of fully scheduledradio resources on a licensed spectrum (controlled by an eNB or thelike).

For a scheduler element, which is for example part of the communicationnetwork control element or connected therewith, in order to make properscheduling decision, examples of embodiments of the invention provide amechanism so as to inform the communication network control elementabout the data amount at the devices that is to be sent over licensedspectrum or for example via D2D resources (e.g. licensed or unlicensedspectrum) in case of a D2D communication. In particular, as a resourceallocation among devices or UEs in a D2D connection may possibly notaccurately followed by the scheduling eNB, in order to considercorresponding resource allocations, the device provides the eNB withinformation about the data amount at the devices that is to be sent overlicensed and unlicensed spectrum e.g. in case of a D2D communication orthe like, so as to enable the eNB to make proper scheduling decisionsamong devices.

By means of this, it is possible that the communication network controlelement, such as the eNB, can conduct a proper control, i.e. allocationof resources on the licensed band, for different connection types, suchas connection of devices with only a cellular communication mode onlicensed spectrum, of devices with a cellular and a D2D communicationmode on licensed spectrum, of devices with a cellular communication modeon both licensed and unlicensed spectrum, and of devices with a cellularcommunication mode on licensed spectrum and a D2D communication mode onunlicensed spectrum.

In other words, according to examples of embodiments of the invention,information can be conveyed to the communication network controlelement, such as the eNB, about the share of controlled data, i.e. datatransmitted in a scheduled manner on a licensed spectrum, and the shareof at least partially non-controlled data, i.e. data sent in a D2Dcommunication or data sent over unlicensed spectrum (data for which noresources on the licensed spectrum have to be allocated by the eNB), inorder to enable the communication network control element to make aresource allocation onto the licensed spectrum which does notoverestimate the data amount to be transmitted, i.e. a resourceallocation which does not unnecessarily decrease the amount of availableresources for other users.

FIG. 1 shows a diagram illustrating a configuration of a communicationsystem in which examples of embodiments of the invention can beimplemented. It is to be noted that FIG. 1 shows a simplifiedarchitecture of an exemplary communication system for illustrating ascenario where examples of embodiments of the present invention areapplicable. Specifically, FIG. 1 shows a 3GPP LTE based communicationnetwork configuration where a base station, i.e. an eNB 10, is providedand a UE 20 is located in a cell region where communication with the eNB10 is possible.

It is to be noted that the network architecture shown in FIG. 1 depictsonly those network elements which are useful for understanding theprinciples of the examples of embodiments of the invention. As known bythose skilled in the art there are several other network elementsinvolved in the establishment, control and management of a communicationconnection which are omitted here for the sake of simplicity.

Referring to FIG. 1, reference sign 10 denotes the eNB as an example fora communication network control element. Reference sign 20 denotes acommunication network element, such as a UE, which is capable ofconducting a communication via an interface to a shared or unlicensedspectrum (indicated by US in FIG. 1), and of conducting a communicationvia an interface to a licensed spectrum (indicated by LS in FIG. 1). TheeNB 10 receives, according to examples of embodiments of the invention,specific buffer status information from the UE 20, while the UE 20receives from the eNB 10 setting information (configuration information)and corresponding instructions to follow the setting information.

It is to be noted that the eNB 10 may serve more than one cell oroperators, or may include sub-cells which are served by own basetransceiver stations. Furthermore, the eNB 10 may control more than oneUE.

Reference sign 30 denotes another UE or communication network elementwith which the UE 20 can conduce a D2D communication, for example, e.g.via an unlicensed spectrum.

According to examples of embodiments of the invention, the UE 20 is adevice which is capable of offloading traffic from a band of onespectrum to a band of another spectrum, such as to offload traffic fromthe licensed spectrum to the shared spectrum while sharing a commontransmission buffer with the transmission over a radio interface able tocommunicate on a licensed band.

It is to be noted that the offloading of traffic may be executed, forexample, in a communication between an access point and the UE 20, forexample to a shared band, but also in a communication between devices(i.e. a D2D communication), for example, to a licensed band, or acombination of communications and offloading targets as indicated in theabove discussed list of different connection types. That is, anycombination (from UE point of view) is applicable where the UE may haveboth cellular and D2D modes active simultaneously, and traffic of bothmodes can be conveyed both in licensed and shared/unlicensed spectrum.As a result of offloading, there are necessary less resources on thetransmission bands of the offloaded spectrum by using resources ontransmission bands of the spectrum to which the traffic is offloaded.Therefore, offloading is of interest in particular with regard tolicensed spectrum having a scarcity of resources.

In order to inform the network about the amount of data at the devices(UE) to be transmitted in the UL direction, i.e. of data stored in ULtransmission buffers, for example, the device may transmit buffer statusinformation periodically or at specific events to the communicationnetwork control element, for example the eNB. On the basis of suchbuffer status information, the communication network control element candecide on an allocation of resources to the respective connection of theUE.

In the following, a mechanism for reporting buffer status informationbased on 3GPP MAC specification, which is utilized in 3GPP LTE systems,is described in connection with FIGS. 2 and 3.

FIG. 2 shows a diagram illustrating a grouping of radio bearers intoradio bearer groups used as a basis for signaling buffer statusinformation to the network. FIG. 3 shows a diagram illustrating astructure of buffer status reports forming an example of buffer statusinformation used in examples of embodiments of the invention.

In a LTE based communication system, in order to inform the networkabout the status of transmission buffers at a device, buffer statusreports (BSRs) from the UE to the eNB are used which assist the eNB inits decision for allocating UL resources. BSRs are necessary since inthe UL direction because scheduling decisions are performed in thecommunication network control element (the eNB) while the transmissionbuffer for the data (and hence the initial information about the amountof data to be transmitted) is located in the UE. Therefore, the BSRs aresent from the UE to the eNB by using a MAC control element so as toindicate the amount of data in the UE that needs to be transmitted overUL-SCH.

BSR reporting may be controlled on the basis of e.g. two timers, i.e.periodicBSR-Timer (also referred to as periodic timer) and retxBSR-Timer(also referred to as regular time). Transmission of a BSR may betriggered, for example, when one of the timers expires, or when aspecific event occurs, e.g. when UL data for a logical channel withhigher priority becomes available for transmission, or other eventsbeing known to those skilled in the art.

According to 3GPP specification, buffer status information aretransmitted on a per radio bearer group basis. FIG. 2 shows an exampleof a grouping or mapping of radio bearers into RBGs. Specifically, asshown in FIG. 2, a maximum of four RBGs, i.e. RBG#1, RBG#2, RBG#3 andRBG#4 are formed from different radio bearers RB#1 to RB#6, wherein oneRBG may be formed by RBs having e.g. similar QoS requirements. It is tobe noted that while FIG. 2 shows four RBGs, in accordance with themaximum number of RBGs according to 3GPP, examples of embodiments of theinvention are also usable with less or more RBGs or similarconstructions, as long as a basis for a transmission of buffer statusinformation is provided.

The buffer status of the radio bearers (the boxes at the RBs indicate anexample of a transmission buffer wherein the grey portions represents acorresponding amount of data for transmission) mapped to a respectiveRBG is sent in the form of an BSR to the communication network controlelement.

For the transmission of the buffer status by means of the BSR, there aretwo types of BSR defined in LTE, which are illustrated in FIG. 3. Thefirst type is a so-called short buffer status report, and the secondtype is a so-called long buffer status report BSR.

In the short BSR, the RBG to which the BSR is related is identified in afirst field (e.g. 2 bits Ion), while the actual value of the buffer sizeis added in a second field (e.g. 6 bits long); that is, the short BSR issent for only one RBG.

On the other hand, in the long BSR, the buffer sizes of each RBG isindicated in a corresponding field in a consecutive manner (i.e.starting from RBG#1 and ending at RBG#4), wherein each field is e.g. 6bits long.

Which one of the long and short BSR is transmitted may depend, forexample, on the amount of available uplink transmission resources forsending the BSR, on how many groups of logical channels have non-emptybuffers, and on whether a specific event is triggered at the UE.

In the following, examples of embodiments of the invention are describedin which buffer status information is transmitted from a communicationnetwork element, such as e.g. UE 20 in FIG. 1, is transmitted to acommunication network control element, such as the eNB 10 in FIG. 1, andthe buffer status information is processed for deciding on theallocation of resources for transmission over at least one spectrum,e.g. the licensed spectrum. According to some of the following examples,the communication network control element is also arranged to configurea setting of the communication network element with regard to thecontent of buffer status information, and to conduct a specificprocessing in accordance with a mode indication of the communicationnetwork element.

FIG. 4 shows a flow chart illustrating a basic procedure for signalingbuffer status information which conducted in a communication networkelement according to examples of embodiments of the invention. On theother hand, in FIG. 5, a flow chart is shown illustrating a procedurefor processing the buffer status information which is conducted in acommunication network control element according to examples ofembodiments of the invention.

According to FIG. 4, in step S10, when a communication network elementsuch as the UE 20 according to FIG. 1 conduct an offloading processingfor offloading traffic from a transmission via one spectrum, e.g.licensed spectrum, to a transmission via another spectrum, e.g.unlicensed spectrum, an offloading value is estimated which indicates anamount of traffic which can be offloaded from the transmission over thelicensed spectrum to a transmission over the unlicensed spectrum. Thatis, the offloading value gives an estimate about an amount of resources(transmission capacity, bandwidth etc.) which can be spared on thelicensed spectrum for transmitting data in the transmission buffers inthe UL direction due to the shift of the data to the transmission overthe unlicensed spectrum.

For example, the offloading value may be estimated on the basis ofhistory information and a result of a throughput calculation related toa preceding offloading of traffic to the unlicensed spectrum, i.e. basedon a preceding offloading result. Also other manners of determining theoffloading value are conceivable.

Then, in step S20, the UE 20 determines buffer sizes of transmissionbuffers used in a transmission over the licensed spectrum and theunlicensed spectrum. For examples, the buffer sizes indicated in FIG. 2are determined on a per RBG basis.

Then, in step S30, the UE 20 sends buffer status information to the eNB10 for indicating the sizes of the transmission buffers for atransmission over the licensed spectrum wherein the estimated offloadingvalue is considered in the buffer size information. In other words, theUE 20 informs the eNB about the amount of data stored in thetransmission buffers but the information sent to the eNB 10 considersalso a reduction of the total amount by the amount of data which can beoffloaded to the other spectrum transmission, for example to theunlicensed spectrum. For example, the value of buffer sizes sent to theeNB 10 may be a result of a subtraction of the actual buffer size andthe offloading value, i.e. a value which represents an amount of datawhich is finally to be transmitted via the controlled, i.e. licensedspectrum.

On the other hand, according to FIG. 5, in step S100, the communicationnetwork control element, such as the eNB 10 of FIG. 1, receives andprocesses buffer status information from a UE (e.g. UE 20) indicating abuffer size for transmission over the licensed spectrum (i.e. the buffersize information sent in step S30 of FIG. 4, for example). That is, thebuffer status information received in step S100 considers an estimatedoffloading value indicating an amount of traffic which can be offloadedfrom a transmission over the licensed spectrum to a transmission overthe unlicensed spectrum, for example.

Then, in step S110, on the basis of the received buffer statusinformation, i.e. under consideration of the amount of data which can beoffloaded to the unlicensed spectrum, the eNB 10 determines the requiredresources for the transmission of the data in the transmission buffersof the UE over the licensed spectrum, wherein the availability ofresources is taken into account (e.g. based on overall traffic amount,transmission restrictions etc.). Thereafter, in step S120, the eNB 10allocates the determined resources to the UL transmission of the UE 20on the licensed spectrum.

According to one example of an embodiment of the invention, the UE 20determines, as buffer sizes for the buffer size information, values ofan actual buffer size and of a virtual buffer size. For example,according to the present example of embodiments of the invention, the UE20 calculates the actual buffer size on the basis of the total amount ofdata in the transmission buffers of the RBG(s) in question, e.g. bycombining the values of the buffer sizes of the different prioritybuffers, and calculates then the virtual buffer size by subtracting anoffloading value from the actual buffer size. Thus, the virtual buffersize indicates the buffer size (or amount of data) being relevant foroperation on the licensed spectrum as it considers the amount of data(deducted from the total amount of data) which can be offloaded to theunlicensed spectrum. In other words, on the basis of the actual buffersize and the virtual buffer size, the extra resources obtained from theoffloading can be determined. For example, the virtual buffer size is:VBS=ABS−EOTA, where

ABS is Actual Buffer Size, EOTA is Estimated Offloading Traffic Amount(offloading value), and VBS is Virtual Buffer Size.

According to examples of embodiments of the invention, the buffer sizeinformation comprises both the ABS and the VBS values.

The virtual buffer size may be, for example, a MAC buffer size.

According to a further example of embodiments of the invention, insteadof transmitting in the buffer size information both of the ABS and theVBS to the eNB 10, it is possible to transmit only the VBS in case ofoffloading traffic.

According to further examples of embodiments of the invention, thetransmission of the buffer size information considers a status of theconnection to which traffic can be offloaded. For example, in case it isdetermined that the offloading connection is terminated, or in case thatan idle state for the offloading connection is determined to be presentfor a predetermined time, the VBS is set to the ABS, and only the ABS isreported to the network.

In a still further example of embodiments of the invention, it ispossible that the VBS value is indicated to be a negative value. Thismay be the case, for example, in case the offloading value can begreater than the ABS, or in case that additional resources are assumedto be present in the unlicensed spectrum so that not only all data inthe considered transmission buffer can be transmitted but even more thanthat. In other another words, a negative VBS value is assumed when moreresources on the unlicensed band are determined to be available thanbeing necessary for covering the present need of the UE.

When the network, i.e. the communication network control element likethe eNB 10 receives the negative VBS, it is recognized by the networkthat there are further resources available on the unlicensed spectrumwhich are usable for offloading. In other words, when the eNB 10determines a negative value for the VBS, in particular from pluraldevices or UEs, it recognizes that there are resources available on theunlicensed spectrum which would allow an even more aggressive offloading

According to a further example of embodiments of the invention, thedevice (UE 20) can assume specific modes corresponding to the factwhether offloading is conducted or not. For example, in case offloadingis conducted, an offloading mode (OM) is assumed which is also indicatedtowards the eNB 10. Otherwise, in case no offloading is conducted, anormal mode (NM) may be assumed which is also indicated to the network.

Depending on the mode indicated by a device (UE 20), the communicationnetwork control element (eNB 10) is arranged to interpret the bufferstatus information, such as a BSR, in different manners.

Assuming an example where there are only 4 RBGs, as indicated above withregard to the LTE system. When it is determined that the UE 20 is in OM,the buffer size information related to one RBG is interpreted asrepresenting a “negative” buffer size. Then, the buffer size of this RBG(i.e. the negative buffer size amount) is deducted from the total buffersize of the other (three) RBGs. Negative values may indicate indirectly,if multiple devices report negative values, to the eNB that there areresources available on unlicensed spectrum and would allow even moreaggressive offloading as one example. That is, allowing negative valueallows above mentioned indirect way of assessing the availability ofunlicensed spectrum on resources used for the offloading.

Alternatively, when the UE 20 is in OM, the eNB 10 may be configured touse one RBG buffer size for the decision on the resources to beallocated.

Furthermore, in another alternative, when the UE 20 is in OM, thenetwork is arranged to restrict the VBS reporting by device (i.e. by UE)and set the OM mode operation as normal mode (NM). This may beconfigured by the communication network control element, i.e. the eNB10, at the UE 20 by means of a corresponding signaling instructing theUE 20 to enter NM, for example.

It is to be noted that in case the UE 20 is in NM, the eNB 10 isconfigured to process the buffer status information in a conventionalmanner, i.e. the network interprets the BSR normally.

According to a further example of embodiments of the invention, thenetwork, i.e. the communication network control element such as the eNB10 is arranged to configure which logical channels or RBGs the UE 20 hasto use for determining the a buffer size, such as the ABS value, whenthe UE 20 is conducting offloading.

In FIG. 6, a block circuit diagram illustrating a configuration of acommunication network control element, such as an eNB, is shown, whichis configured to implement the processing for allocating resources onthe basis of buffer status information as described in connection withthe examples of embodiments of the invention. It is to be noted that thecommunication network control device or eNB 10 shown in FIG. 6 maycomprise several further elements or functions besides those describedherein below, which are omitted herein for the sake of simplicity asthey are not essential for understanding the invention. Furthermore,even though reference is made to an eNB, the communication networkelement may be also another device having a similar function, such as amodem chipset, a chip, a module etc., which can also be part of a BS orattached as a separate element to a BS, or the like.

The communication network control element or eNB 10 may comprise aprocessing function or processor 11, such as a CPU or the like, whichexecutes instructions given by programs or the like related to thebuffer status information processing and control of the UE related tothe buffer status reporting. The processor 11 may comprise one or moreprocessing portions dedicated to specific processing as described below,or the processing may be run in a single processor. Portions forexecuting such specific processing may be also provided as discreteelements or within one or more further processors or processingportions, such as in one physical processor like a CPU or in severalphysical entities, for example. Reference sign 12 denote transceiver orinput/output (I/O) unit connected to the processor 11. The I/O unit 12may be used for communicating with a communication network element likea UE. The I/O unit 12 may be a combined unit comprising communicationequipment towards several network elements, or may comprise adistributed structure with a plurality of different interfaces fordifferent network elements. Reference sign 13 denotes a memory usable,for example, for storing data and programs to be executed by theprocessor 11 and/or as a working storage of the processor 11.

The processor 11 is configured to execute processing related to theabove described mechanism related to the buffer status reporting. Inparticular, the processor 11 comprises a sub-portion 111 as a processingportion which is usable as a buffer status information receivingportion. The portion 111 may be configured to perform processingaccording to step S100 according to FIG. 5, for example. Furthermore,the processor 11 comprises a sub-portion 112 as a processing portionwhich is usable as a resource determination portion. The portion 112 maybe configured, for example, to perform processing according to step S110according to FIG. 5, for example. Moreover, the processor 11 comprises asub-portion 113 as a processing portion which is usable as a resourceallocation portion. The portion 113 may be configured, for example, toperform a processing according to step S120 according to FIG. 5, forexample. In addition, the processor 11 comprises a sub-portion 114 as aprocessing portion which is usable as a recognition processing portionconfigured to recognize that the availability of further resources foroffloading, e.g. from a negative virtual buffer size. Moreover, theprocessor 11 comprises a sub-portion 115 as a processing portion whichis usable as a mode determination portion configured to determine themode of a UE or the like as being in an offloading mode or a normalmode. In addition, the processor 11 comprises a sub-portion 116 as aprocessing portion which is usable as a configuration portion configuredto send configuration information to a UE or the like for defininglogical channels or RBGs to be used in a determination of an actualbuffer size or the like.

In FIG. 7, a block circuit diagram illustrating a configuration of acommunication network element, such as of UE, is shown, which isconfigured to implement the processing as described in connection withthe examples of embodiments of the invention, for example. It is to benoted that the communication network device or UE 20 shown in FIG. 7 maycomprise several further elements or functions besides those describedherein below, which are omitted herein for the sake of simplicity asthey are not essential for understanding the invention. Furthermore,even though reference is made to a UE, the communication network elementmay be also another device having a similar function, such as a modemchipset, a chip, a module etc., which can also be part of a UE orattached as a separate element to a UE, or the like.

The communication network element or UE 20 may comprise a processingfunction or processor 21, such as a CPU or the like, which executesinstructions given by programs or the like related to the buffer statusreporting. The processor 21 may comprise one or more processing portionsdedicated to specific processing as described below, or the processingmay be run in a single processor. Portions for executing such specificprocessing may be also provided as discrete elements or within one ormore further processors or processing portions, such as in one physicalprocessor like a CPU or in several physical entities, for example.Reference sign 22 denotes transceiver or input/output (I/O) unitsconnected to the processor 21. The I/O units 22 may be used forcommunicating with elements of the access network, such as acommunication network control element like an eNB, and with other UEs,e.g. in a direct communication in a D2D mode. The I/O units 22 may be acombined unit comprising communication equipment towards several of thenetwork element in question, or may comprise a distributed structurewith a plurality of different interfaces for each network element inquestion. Reference sign 23 denotes a memory usable, for example, forstoring data and programs to be executed by the processor 21 and/or as aworking storage of the processor 21.

The processor 21 is configured to execute processing related to theabove described mechanism for reporting buffer status information. Inparticular, the processor 21 comprises a sub-portion 211 as a processingportion which is usable as an estimating processing portion. The portion211 may be configured to perform a processing according to step S10according to FIG. 4, for example. Furthermore, the processor 21comprises a sub-portion 212 as a processing portion which is usable as adetermining processing portion. The portion 212 may be configured toperform a processing according to step S20 according to FIG. 4, forexample. Moreover, the processor 21 comprises a sub-portion 213 as aprocessing portion which is usable as a buffer status transmissionprocessing portion. The portion 213 may be configured to performprocessing according to step S30 according to FIG. 4, for example. Inaddition, the processor 21 comprises a sub-portion 214 as a processingportion which is usable as a mode setting processing/indicating portionconfigured to set the communication network element in an offloadingmode or a normal mode, and to indicate the set mode to the communicationnetwork control element. Moreover, the processor 21 comprises asub-portion 215 as a processing portion which is usable as aconfiguration processing portion configured to receive and processconfiguration information from the communication network control element(e.g. the eNB) or the like defining logical channels or RBGs to be usedin a determination of an actual buffer size or the like.

As described above, examples of embodiments of the invention concerningthe reporting and processing of buffer status information when acommunication via licensed and unlicensed spectrum is conducted aredescribed to be implemented in UEs and eNBs. However, the invention isnot limited to this. For example, examples of embodiments of theinvention may be implemented in any wireless modems or the like.

According to a further example of embodiments of the invention, there isprovided an apparatus comprising estimating processing means forestimating an offloading value indicating an amount of traffic which canbe offloaded from a transmission over a licensed spectrum to atransmission over an unlicensed spectrum, determining processing meansfor determining a buffer size of at least one transmission buffer usedin a transmission over the licensed spectrum and the unlicensedspectrum, and buffer status information transmission processing meansfor sending a buffer status information indicating the buffer size fortransmission over the licensed spectrum under consideration of theestimated offloading value.

Moreover, according to an example of embodiments of the invention, thereis provided an apparatus comprising a buffer status informationreceiving means for receiving and processing a buffer status informationindicating a buffer size for transmission over a licensed spectrum,wherein the buffer status information considers an estimated offloadingvalue indicating an amount of traffic which can be offloaded from atransmission over a licensed spectrum to a transmission over anunlicensed spectrum, resource determination means for determining, onthe basis of the received buffer status information, required resourcesfor a transmission over the licensed spectrum, and resource allocationmeans for allocating the determined resources to a transmission over thelicensed spectrum.

According to a further aspect A, examples of embodiments of theinvention are related to a method comprising receiving and processing abuffer status information indicating a buffer size for transmission overa licensed spectrum, wherein the buffer status information considers anestimated offloading value indicating an amount of traffic which can beoffloaded from a transmission over a licensed spectrum to a transmissionover an unlicensed spectrum, determining, on the basis of the receivedbuffer status information, required resources for a transmission overthe licensed spectrum, and allocating the determined resources to atransmission over the licensed spectrum.

According to a further aspect A1, in the method according to aspect A,there are further comprised receiving and processing, as the bufferstatus information, at least one of an actual buffer size oftransmission buffers based on a combination of buffer sizes of differentpriority buffers of a communication network element, and a virtualbuffer size which is calculated by subtracting a parameter correspondingto the estimated offloading value from the actual buffer size.

According to a further aspect A2, in the method according to aspect A1,there are further comprised receiving and processing buffer statusinformation indicating a negative value for a virtual buffer size,wherein the method further comprises conducting a recognition processingfor recognizing, when a negative value for the virtual buffer size isreceived, an availability of further resources for offloading to atransmission over the unlicensed spectrum.

According to a further aspect A3, in the method according to aspect A,there are further comprised receiving and processing a mode indicationindicating whether a communication network element is set into anoffloading mode where traffic is offloaded to a transmission over theunlicensed spectrum, or into a normal mode when offloading of traffic isstopped, wherein, when the mode of the communication network element isthe offloading mode, the method further comprises interpreting one ofindicated buffer sizes as a negative buffer size and subtracting thebuffer size interpreted as a negative buffer size from a sum of otherbuffer sizes indicated in the buffer status information, and using theresult of the subtraction for the determination of the requiredresources for the transmission over the licensed spectrum.

According to a further aspect A4, in the method according to aspect A1,there are further comprised receiving and processing a mode indicationindicating whether a communication network element is set into anoffloading mode where traffic is offloaded to a transmission over theunlicensed spectrum, or into a normal mode when offloading of traffic isstopped, wherein, when the mode of the communication network element isthe offloading mode, the method further comprises restricting a virtualbuffer size reporting by a communication network element and setting theoffloading mode operation as a normal mode.

According to a further aspect A5, in the method according to aspect A,the buffer status information is related to at least one radio bearergroup formed from one or more logical channels, wherein the methodfurther comprises selecting logical channels or radio bearer groupswhich are to be used for determining the buffer size when offloading isexecuted by the communication network element, and sending aninstruction to a communication network indicating the selected logicalchannels or radio bearer groups.

According to a further aspect B, examples of embodiments of theinvention are related to a computer program product for a computer,comprising software code portions for performing the steps of any ofaspects A and A1 to A5 when said product is run on the computer. Thecomputer program product according to aspect B may comprise acomputer-readable medium on which said software code portions arestored. Alternatively or additionally, the computer program productaccording to aspect B is directly loadable into the internal memory ofthe computer and/or transmittable via a network by means of at least oneof upload, download and push procedures.

For the purpose of the present invention as described herein above, itshould be noted that

-   -   an access technology via which signaling is transferred to and        from a network element may be any technology by means of which a        network element or sensor node can access another network        element or node (e.g. via a base station or generally an access        node). Any present or future technology, such as WLAN (Wireless        Local Access Network), WiMAX (Worldwide Interoperability for        Microwave Access), LTE, LTE-A, Bluetooth, Infrared, and the like        may be used; although the above technologies are mostly wireless        access technologies, e.g. in different radio spectra, access        technology in the sense of the present invention implies also        wired technologies, e.g. IP based access technologies like cable        networks or fixed lines but also circuit switched access        technologies; access technologies may be distinguishable in at        least two categories or access domains such as packet switched        and circuit switched, but the existence of more than two access        domains does not impede the invention being applied thereto,    -   usable communication networks and transmission nodes may be or        comprise any device, apparatus, unit or means by which a        station, entity or other user equipment may connect to and/or        utilize services offered by the access network; such services        include, among others, data and/or (audio-) visual        communication, data download etc.;    -   a user equipment or communication network element may be any        device, apparatus, unit or means by which a system user or        subscriber may experience services from an access network, such        as a mobile phone, personal digital assistant PDA, or computer,        or a device having a corresponding functionality, such as a        modem chipset, a chip, a module etc., which can also be part of        a UE or attached as a separate element to a UE, or the like;    -   method steps likely to be implemented as software code portions        and being run using a processor at a network element or terminal        (as examples of devices, apparatuses and/or modules thereof, or        as examples of entities including apparatuses and/or modules for        it), are software code independent and can be specified using        any known or future developed programming language as long as        the functionality defined by the method steps is preserved;    -   generally, any method step is suitable to be implemented as        software or by hardware without changing the idea of the        invention in terms of the functionality implemented;    -   method steps and/or devices, apparatuses, units or means likely        to be implemented as hardware components at a terminal or        network element, or any module(s) thereof, are hardware        independent and can be implemented using any known or future        developed hardware technology or any hybrids of these, such as a        microprocessor or CPU (Central Processing Unit), MOS (Metal        Oxide Semiconductor), CMOS (Complementary MOS), BiMOS (Bipolar        MOS), BiCMOS (Bipolar CMOS), ECL (Emitter Coupled Logic), TTL        (Transistor-Transistor Logic), etc., using for example ASIC        (Application Specific IC (Integrated Circuit)) components, FPGA        (Field-programmable Gate Arrays) components, CPLD (Complex        Programmable Logic Device) components or DSP (Digital Signal        Processor) components; in addition, any method steps and/or        devices, units or means likely to be implemented as software        components may for example be based on any security architecture        capable e.g. of authentication, authorization, keying and/or        traffic protection;    -   devices, apparatuses, units or means can be implemented as        individual devices, apparatuses, units or means, but this does        not exclude that they are implemented in a distributed fashion        throughout the system, as long as the functionality of the        device, apparatus, unit or means is preserved; for example, for        executing operations and functions according to examples of        embodiments of the invention, one or more processors may be used        or shared in the processing, or one or more processing sections        or processing portions may be used and shared in the processing,        wherein one physical processor or more than one physical        processor may be used for implementing one or more processing        portions dedicated to specific processing as described,    -   an apparatus may be represented by a semiconductor chip, a        chipset, or a (hardware) module comprising such chip or chipset;        this, however, does not exclude the possibility that a        functionality of an apparatus or module, instead of being        hardware implemented, be implemented as software in a (software)        module such as a computer program or a computer program product        comprising executable software code portions for execution/being        run on a processor;    -   a device may be regarded as an apparatus or as an assembly of        more than one apparatus, whether functionally in cooperation        with each other or functionally independently of each other but        in a same device housing, for example.

As described above, there is provided a mechanism for reporting bufferstatus information to a communication network control element whentransmission via both a licensed and an unlicensed spectrum is conductedand offloading of traffic is executed. After an offloading valueindicating the amount of traffic which can be offloaded from atransmission over a licensed spectrum to a transmission over anunlicensed spectrum is estimated, the UE determines a buffer size of atleast one transmission buffer used in a transmission over the licensedspectrum and the unlicensed spectrum. Then, buffer status information issent to the eNB wherein the estimated offloading value is considered.The eNB can then allocate resources for the transmission over thelicensed band while benefits by the offloading to the unlicensed bandare considered in the resource allocation.

Although the present invention has been described herein before withreference to particular embodiments thereof, the present invention isnot limited thereto and various modifications can be made thereto.

The invention claimed is:
 1. An apparatus comprising: an estimatingprocessing portion configured to estimate an offloading value indicatingan amount of traffic which can be offloaded from a first transmissionover a licensed spectrum to a second transmission over an unlicensedspectrum, a determining processing portion configured to determine afirst buffer size of at least one transmission buffer to be used in thefirst transmission over the licensed spectrum, wherein the first buffersize is an actual buffer size of the at least one transmission bufferdetermined by combining buffer sizes of different priority buffers,wherein the determining processing portion is further configured tocalculate a second buffer size for a third transmission over thelicensed spectrum under consideration of the estimated offloading valueand the second buffer size is a virtual buffer size which is calculatedby subtracting a parameter corresponding to the estimated offloadingvalue from the actual buffer size, and a buffer status informationtransmission processing portion configured to send buffer statusinformation indicating the calculated second buffer size.
 2. Theapparatus according to claim 1, wherein the estimating processingportion is configured to estimate the offloading value on the basis ofhistory information and a result of a throughput calculation related toa preceding offloading of traffic to the unlicensed spectrum.
 3. Theapparatus according to claim 1, wherein, when a connection foroffloading traffic to the unlicensed spectrum is terminated ordetermined to be idle for a predetermined time, the buffer statusinformation transmission portion is configured to send buffer statusinformation based on the actual buffer size.
 4. The apparatus accordingto claim 1, wherein, when the parameter corresponding to the estimatedoffloading value is greater than the actual buffer size, the bufferstatus information transmission portion is configured to send bufferstatus information indicating a negative virtual buffer size.
 5. Theapparatus according to claim 1, further comprising a mode settingprocessing portion configured to set a communication network elementinto one of an offloading mode when traffic is offloaded to theunlicensed spectrum, and a normal mode when offloading of traffic to theunlicensed spectrum is stopped, and a mode indicating processing portionconfigured to indicate the mode set for the communication networkelement together with the buffer status information.
 6. The apparatusaccording to claim 1, wherein the buffer status information is relatedto at least one radio bearer group formed from one or more logicalchannels, wherein the apparatus further comprises a configurationprocessing portion configured to receive an instruction for selectinglogical channels or radio bearer groups which are to be used fordetermining the buffer size when offloading is executed.
 7. An apparatuscomprising: a buffer status information receiving portion configured toreceive and process buffer status information indicating a buffer sizefor transmission over a licensed spectrum, wherein the buffer sizeconsiders an estimated offloading value indicating an amount of trafficwhich can be offloaded from a first transmission over a licensedspectrum to a second transmission over an unlicensed spectrum, aresource determination portion configured to determine, on the basis ofthe received buffer status information, required resources for a thirdtransmission over the licensed spectrum, and a resource allocationportion configured to allocate the determined resources to the thirdtransmission over the licensed spectrum, wherein the buffer statusinformation includes: a first buffer size of at least one transmissionbuffer to be used in the first transmission over the licensed spectrumand the first buffer size is an actual buffer size of transmissionbuffers based on a combination of buffer sizes of different prioritybuffers of a communication network element, and a second buffer size forthe third transmission over the licensed spectrum and the second buffersize is a virtual buffer size that considers the estimated offloadingvalue by subtracting a parameter corresponding to the estimatedoffloading value from the actual buffer size.
 8. The apparatus accordingto claim 7, wherein the buffer status information receiving portion isconfigured to receive and process buffer status information indicating anegative value for a virtual buffer size, wherein the apparatus furthercomprises a recognition processing portion configured to recognize, whena negative value for the virtual buffer size is received, anavailability of further resources for offloading to a transmission overthe unlicensed spectrum.
 9. The apparatus according to claim 7, furthercomprising a mode determination processing portion configured to receiveand process a mode indication indicating whether a communication networkelement is set into an offloading mode where traffic is offloaded to atransmission over the unlicensed spectrum, or into a normal mode whenoffloading of traffic is stopped, wherein, when the mode of thecommunication network element is the offloading mode, the buffer statusinformation receiving portion is further configured to interpret one ofindicated buffer sizes as a negative buffer size and to subtract thebuffer size interpreted as a negative buffer size from a sum of otherbuffer sizes indicated in the buffer status information, wherein theresult of the subtraction is used by the resource determination portionfor the determination of the required resources for the transmissionover the licensed spectrum.
 10. The apparatus according to claim 7,further comprising a mode determination processing portion configured toreceive and process a mode indication indicating whether a communicationnetwork element is set into an offloading mode where traffic isoffloaded to a transmission over the unlicensed spectrum, or into anormal mode when offloading of traffic is stopped, wherein, when themode of the communication network element is the offloading mode, thebuffer status information receiving portion is further configured torestrict a virtual buffer size reporting by a communication networkelement and to set the offloading mode operation as a normal mode. 11.The apparatus according to claim 7, wherein the buffer statusinformation is related to at least one radio bearer group formed fromone or more logical channels, wherein the apparatus further comprises aconfiguration portion configured to select logical channels or radiobearer groups which are to be used for determining the buffer size whenoffloading is executed by the communication network element, and to sendan instruction to a communication network indicating the selectedlogical channels or radio bearer groups.
 12. A method comprising:estimating an offloading value indicating an amount of traffic which canbe offloaded from a first transmission over a licensed spectrum to asecond transmission over an unlicensed spectrum, determining a firstbuffer size of at least one transmission buffer to be used in the firsttransmission over the licensed spectrum, wherein the first buffer sizeis an actual buffer size of the at least one transmission bufferdetermined by combining buffer sizes of different priority buffers,calculating a second buffer size for a third transmission over thelicensed spectrum under consideration of the estimated offloading valueand the second buffer size is a virtual buffer size which is calculatedby subtracting a parameter corresponding to the estimated offloadingvalue from the actual buffer size, and sending buffer status informationindicating the calculated second buffer size.
 13. The method accordingto claim 12, wherein the offloading value is estimated on the basis ofhistory information and a result of a throughput calculation related toa preceding offloading of traffic to the unlicensed spectrum.
 14. Themethod according to claim 12, wherein, when a connection for offloadingtraffic to the unlicensed spectrum is terminated or determined to beidle for a predetermined time, buffer status information based on theactual buffer size is sent.
 15. The method according to claim 12,wherein, when the parameter corresponding to the estimated offloadingvalue is greater than the actual buffer size, buffer status informationindicating a negative virtual buffer size is sent.
 16. The methodaccording to claim 12, further comprising setting a communicationnetwork element into one of an offloading mode when traffic is offloadedto the unlicensed spectrum, and a normal mode when offloading of trafficto the unlicensed spectrum is stopped, and indicating the mode set forthe communication network element together with the buffer statusinformation.
 17. The method according to claim 12, wherein the bufferstatus information is related to at least one radio bearer group formedfrom one or more logical channels, the method further comprisingreceiving and executing an instruction for selecting logical channels orradio bearer groups which are to be used for determining the buffer sizewhen offloading is executed.